A Blackhawk at gross weight is in the heavy turbulence area of VRS at 26 knots and 1700 FPM, and may still be in the light turbulence regions at speeds as high as 80 knots. That is a really big area to avoid.
No.
The higher the disc loading, the higher the speed of the downwash and therefore the higher your RoD needs to be in order to catch up with your downwash.
Light helicopters with low disc loadings are much more susceptible to VRS.
They are also more susceptible to SWP since they run out of power quickly.
Do we really need to go round this buoy again and again?
If you are going to hover OGE, make sure you have enough performance to do so with pre-flight planning and a power available check. Ideally have some performance to spare to allow for turbulence, mishandling etc.
Don't make downwind approaches, especially to OGE, without thinking carefully about it and ensuring you have even more power in hand.
If you want to come to an OGE hover make it a level approach in the latter stages as it uses less power (you don't have to kill RoD) and it is easy to spot if you are getting close to your power limit.
Give yourself a escape route of clear air you can fly into.
If you are below ETL (10 - 15 Kts) and you have more than 3 or 400 ft/min RoD with power applied, you are right in the bracket for IVRS which could quickly become VRS - just avoid low speed descents.